Immunotherapy is a promising approach for treating metastatic malignancies that have failed conventional agents. We have demonstrated the safety and feasibility of active immunotherapy with carcinoembryonic antigen (CEA) peptide loaded-dendritic cells (DC), the most important antigen presenting cells (APC), in patients with advanced cancers. Furthermore, preliminary analysis demonstrates the induction of detectable CEA-specific immune responses in the peripheral blood of the immunized patients. The DC generation requires multiple manipulations of the cellular product, a prolonged period of in vitro culture, and the use of two cytokines, which increase the expense and complexity of the vaccine. Therefore, a more efficient approach to the generation of an APC vaccine is warranted.